Certain-2-substituted-1,2,3,4-tetrahydro-beta or gamma carbolines

ABSTRACT

A new series of closely related compounds, the Beta - and Delta -carbolines carrying on the piperidino-nitrogen an unsaturated hydrocarbon side chain with three carbon atoms, was found to possess valuable anti-depressant activity with an unusually high therapeutic index.

United States Patent Garmaise et al.

[ Feb. 27, 1973 CERTAIN-2-SUBSTITUTED-l,2,3,4- TETRAHYDRO-BETA OR GAMMA CARBOLINES Inventors: David Lyon Garmaise, Montreal;

Gerard Yvon Paris, Duvernay, Quebec, both of Canada; Nicholas Peter Plotnikoif, Lake Bluff, lll.

Assignee: Abbott Laboratories, North Chicago, Ill.

Filed: Dec. 3, 1970 Appl. No.: 94,984

US. Cl. ..260/296 A, 424/263 Int. Cl. ..C07d 31/42 Field of Search ..260/296 A References Cited OTHER PUBLICATIONS Winterfeldt et al., Chem. Ber. 100 (11) pages 3801-3807 (1967).

Primary ExaminerAlan L. Rotman Attorney-Robert L. Niblack [57] ABSTRACT 6 Claims, No Drawings CERTAIN-2-SUBSTITUTED-l ,2,3 ,4- TETRAHYDRO-BETA OR GAMMA CARBOLINES DETAILED DESCRIPTION OF THE INVENTION Anti-depressants have become an important pharmaceutical class of drugs useful in many depressive states but many of the compounds used to date unfortunately have various side effects such as relatively high toxicity which raises the danger of overdosage emetic reactions or secondary effects on the central nervous 6 4 9 1 I NR R and R l R, A)

wherein R is hydrogen, methyl or fluorine and wherein R' is propargyl or allyl. These compounds are more often referred to as substituted l,2,3,4- tetrahydropyridoindoles; particularly, the above ,B-carbolines are identified as l,2,3,4-tetrahydro-9H-pyrido [3,4-b]indoles and the A-carbolines are referred to as l,2,3,4-tetrahydro 5H-pyrido[4,3-b]indoles. The LD of these compounds, upon oral administration, is above 1000 mg'./kg. while the intraperitoneal LD values vary between 500 and above 1000 mg./kg. The anti-depressant activity of the new compounds was measured by the method of GM. Everett, described in Excerptia Int. Congress, Series 122, page 164-7. This test is commonly referred to as modified DOPA-test and uses an activity scale of 1-3 with activity 3 signifying a pronounced anti-depressant effect. Most of the new compound have an activity on this scale ranging between 1 and 3 at an oral dose of 25 mg./kg. and in all cases, significant activity is found at 100 mg./kg. in animals.

The new compounds can easily be prepared by reacting the properly substituted B- and A-carbolines with allyl bromide or propargyl bromide in a suitable inert, organic reaction medium, using a 50 to 100 percent excess of the carboline over the molar equivalent amount of the hydrocarbon bromide. Usually, the ensuing yields are 60 percent or above, even when working on a very small scale.

In order to illustrate the preparation of making the new compounds, reference is made to the following examples, which however, are not intended to limit the invention in any respect.

EXAMPLE 1 2-Propargyl-6-Methyll ,2,3,4-Tetrahydro-9H-Pyrido[ 3,4-b]lndole To a solution of 5.6 g. of 6-methyl-l,2,3,4- tetrahydro-9Hpyrido[3,4-b]indole in 100 ml. of N,N- dimethylformamide is added 1.8 g. of propargyl bromide. The reaction mixture is stirred at room temperature for 30 minutes and then evaporated to dryness. The residue is treated with 200 ml. of acetone and excess 6-methyl-fl-carboline hydrobromide is filtered off.

. l but The filtrate is again evaporated to dryness to yield l.7 g. of 2-propargyl-6-methyl-l,2,3,4-tetrahydro-9H- pyrido{3,4-b]indole melting at ll92 C. after further recrystallization from ethanol. This compound shows an oral activity of 2 on the above described modified DOPA-test scale at 25 mg./kg. in mice.

EXAMPLE 2 2-Propargyl-8-Methyl-1,2,3,4-Tetrahydro-9I-I-Pyrido[ 3,4-b]lndole By repetition of the procedure described in Example using 8-methyl-l ,2,3,4-tetrahydro-9H- pyrido[3,4-b]indole as the starting material, 2-pr0pargyl-S-methyl- I ,2,3 ,4-tetrahydro-9l-Ipyrido 3 ,4-b indole is obtained in a yield of 65 percent of theory. An analytical sample obtained by ethanol recrystallization melts at l76178 C. It shows activity I at 25 mg./kg. and activity 2 at mg./kg. after oral administration to mice.

EXAMPLE 3 2-Propargyl-1,2,3 ,4-Tetrahydro-9H-Pyrido[ 3 ,4-b Indole By using unsubstituted l,2,3,4-tetrahydro-9l-l-pyrido [3,4-b1l, 2-propargyl- 1 ,2,3 ,4-tetrahydro-9H-pyrido[3 ,4-b]indole is obtained in a yield of 52 percent showing a melting point of 206208 C. after recrystallization from ethanol. The compound shows an activity of 2 at an oral dose of 25 mg./kg. in mice.

EXAMPLE 4 EXAMPLE 5 2-Allyl-6-Fluorol ,2,3 ,4-Tetrahydro-9I-I-Pyrido[ 3 ,4- b]lndole In a repetition of the procedure shown in Example 4 but using allyl bromide as the co-reactant, 2-allyl-6- fluoro-l,2,3,4-tetrahydro-9H-pyrido[3,4-b]indole is obtained in a yield of 64%. An analytical sample melts at 128-l30 C. (ethanol) and the compound shows an activity of2 at an oral dose of 25 mg./kg. in mice.

EXAMPLE 6 2-Allyl-6-Methyll ,2,3,4-Tetrahydro-9H-Pyridol 3,4- b]lndole Hemihydrate In a repetition of Example 1 but using 1.8 g. of allyl bromide in place of propargyl bromide, 2-allyl-6- methyl-1,2,3 ,4-tetrahydro-9H-pyrido[ 3 ,4-blindole hemihydrate is obtained in a yield of 68 percent of theory. An analytical sample melts at 144l46 C. (ethanol).

EXAMPLE 7 2-Allyll ,2,3',4-Tetrahydro-9I-I-Pyrido 3 ,4-b Indole By repeating the procedure of Example 3 but using allyl bromide as the co-reactant, 2-allyl-l,2,3,4- tetrahydro-9l-l-pyrido[3,4-b]indole is obtained in a yield of 63% of theory. An analytical sample melts at 153-155 C. (ethanol) and the compound shows an activity of 3 in the above modified DOPA test at an oral dose of 100 mg./kg. in mice.

EXAMPLE 8 2-Allyl-8-Fluoro-1 ,2,3 ,4-Tetrahydro-5l-l-Pyrido[4,3- b]lndole Hydrochloride A mixture of 10.2 g. of 8-fluoro-l ,2,3,4-tetrahydro-5 l-l-pyrido[4,3-b]indole hydrochloride, 6.8 g. of allyl bromide, 11.2 g. of anhydrous potassium carbonate and 11.3 g. of potassium iodide in 130 ml. of N,N- dimethylformamide is heated for 7 hours at 80-85 C. The mixture is then cooled and poured in 1 liter of water. The organic layer is extracted with 3 portions of 50 ml. each of chloroform. The chloroform extracts are combined, washed with water, dried over magnesium sulfate and evaporated under reduced pressure. The residue is treated with methanolic hydrochloric acid to give 2-allyl-8-fluoro-l ,2,3,4-tetrahydro-SH-pyrido[4,3- b]indole hydrochloride in a yield of 2.3 g. An analytical sample of this salt melts at 27l-2l9 C. (methanol) and shows an activity of 1 at 100 mg./kg. upon oral administration to mice. This compound is also found to be highly active against T. cruzi, showing a minimum inhibitory concentration of 1 part per million on an in vitro test.

As seen from the above examples, the new compounds can be prepared in an extremely simple fashion and they are obtained in good yields. Also, as shown above, these compounds are highly active as antidepressants at low doses while their toxicity is so low that in most instances, a LD cannot be established.

The new compounds can be administered orally or intraperitoneally and are preferably used in form of their non-toxic acid addition salts. Among these salts are the succinate, acetate, citrate, tartrate,

hydrochloride, phosphate, sulfate and the like. The free base or its salts can easily be compounded into standard pharmaceutically acceptable dosage forms such as pills, tablets, syrups, wafers, capsules and the like. They can be combined with the usual excipients such as fillers, flavoring agents, coloring agents and other pharmaceutically acceptable diluents.

The [3- or A-carbolines described above or their nontoxic acid addition salts are preferably administered orally to warm-blooded animals to alleviate depressions at a single dose of between 10 and mg./kg. of body weight or at a daily dose of between l-lOO mg./kg. body weight. In large animals, one-half of this dose range or less is usually sufficient and, if parenteral administration is desired, the above dose range can easily be reduced to between 25 and 50 percent.

We claim:

1. A B- or A-carboline of the formula BUT 1 H 11M,

Nsv N wherein R is methyl or fluorine and R is propargyl or all 1 or a non-toxic acid addition salt thereof.

. The B-carbolme of claim 1 wherein R is attached 

2. The Beta -carboline of claim 1 wherein R is attached at the 6-position.
 3. The Delta -carboline of claim 1 wherein R is attached to the 8-position.
 4. The Beta -carboline of claim 1 wherein R is fluorine in the 6-position and R'' is allyl.
 5. The Beta -carboline of claim 1 wherein R is methyl in the 6-position and R'' is propargyl.
 6. The Beta -carboline of claim 1 wherein R is fluorine in the 6-position and R'' is propargyl. 